Have you read Zen and the Art of Motorcycle Maintenance? It's the best-selling philosophy book of all time. I actually only read it fairly recently, and was stunned at how relevant it was. It was written in the 70s, yet even includes a few passages about computers! It's not about zen, or about motorcycle maintenance. But they both make appearances. I'd recommend giving it a go if you get the chance. It might make Zen and Tao seem a bit less New-Agey to you.

Or, you could check out my personal introduction to the Tao... The Tao of Pooh. I read it when I was a teenager, thinking it positively absurd that anyone would create a book attempting to explain an ancient school of philosophy through Winnie the Pooh. It's not absurd. I found it sublime, and the idea of taoism made a powerful impression on me and probably played a sizable role in driving me to further study of philosophy.

I’m not sure that something that pre-dates the printing press can be considered ‘new age’

What do you mean? It's a great quote. I've been savoring it all day.